A control system for a passenger protecting apparatus for an automotive vehicle with the use of an air bag or a seat belt is disclosed in Japanese Patent Laid Open No. 63-503531 (corresponding to PCT/DE87/00078), for instance. In this control system, a deceleration of an automotive vehicle is detected by a deceleration sensor. The detected deceleration is compared with an Integration threshold. When the deceleration exceeds the integration threshold, the deceleration beyond the integration threshold is integrated. The integrated deceleration is further compared with a predetermined value. When the integrated deceleration exceeds the predetermined value, a passenger protecting apparatus is activated. Further, the integration threshold value is changed according to the magnitude of the integration value, in order to protect a passenger more securely according to various modes of collisions.
In the above-mentioned prior art control system for a passenger protecting apparatus, however, since the integration threshold is adjusted finely according to various collision modes, there exists a problem in that the adjustment process is complicated and further it takes a time to adjust the integration threshold.